A US woman who shot and killed her husband and two adult children before taking her own life is thought to have committed the shocking crime as a result of being ostracised from the religion she was raised in.

Every time I tell a mate I’m doing a story on cryptocurrency, they invariably ask me the same two questions: should they invest their own hard-earned money, and which cryptocurrency will get them a Lamborghini/yacht/island quickest?

'Scarily calm' man in Newcastle stand-off

A man wanted over a triple stabbing is refusing to budge from a residential rooftop in Newcastle after spending more than nine hours in a stand-off with police.

In a surprise twist, it's been revealed the man also allegedly stole a car owned by Australian Rugby Union chief executive Bill Pulver before climbing on to the roof of the townhouse in Tighes Hill around midday Tuesday.

The man is wanted over Monday night's triple stabbing at a Sydney gym and two subsequent armed robberies at service stations.

Three men are in hospital after they were stabbed at the fitness centre in Sydney's Brookvale about 8pm on Monday, with the attacker then driving away in the stolen vehicle before allegedly robbing two service stations in Newcastle.

Mr Pulver's car was stolen at a car wash.

Some residents of the street weren't being allowed inside their homes on Tuesday night with several roads blocked off for the police operation as the man refused to come down from the roof.

With the sun setting, police were using large spotlights on the man as he wandered on the roof in just a pair of shorts.